Discount Cost Calculator: what knocking 10% off really costs

A discount does not come out of the price. It comes out of the profit, which is a much smaller number. Put in your own figures to see what you give away and how much extra work you would have to win just to stand still. Free, and no signup needed.

Is this you?

If two or more sound familiar, the discount is probably costing more than the work it wins. The calculator below puts a number on it.

These boxes are filled in with an example job, not a real one. Replace each number with your own.

Materials, subcontractors, and your own time at a rate you would pay someone else.

Profit at your normal price$0
Profit after the discount$0
Profit given away on this job$0
Share of your profit that is0%
Extra work needed to earn the same0%
Given away across a yearNot entered

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Why a discount costs more than it looks

The number you knock off comes from the price, but it is taken out of the profit, and the profit is a much smaller number. That is the whole problem in one sentence.

Take a $2,000 job that costs you $1,300 to do. Your profit is $700, which is a healthy 35% margin. Knock 10% off and the client saves $200. You do not lose 10%, you lose $200 of $700, which is nearly a third of what the job was worth to you. To earn the same money on the discounted price you would need to win 40% more work.

The thinner your margin, the worse the arithmetic gets. On a 20% margin, a 10% discount halves your profit and you need to double your workload to stand still.

What it costs if nothing changes

At least half of small businesses charge no more for their regular items than they did 18 months earlier: the typical price change is 0%.

Source: Billbooks invoice data, 8,483 invoices from 112 small businesses, September 2024 to September 2026 (aggregate only, figures shown only where 25+ businesses contribute).

That is the background against which most discounts are given. Prices that have not moved in a year and a half are already losing ground to your own costs, and a discount on top of a flat price is a second cut in the same direction.

Discounts also tend not to stay one-off. A client who got 10% once opens the next conversation from the discounted price, so the discount quietly becomes your new rate for that client, and the cost is not one job, it is every job after it.

How much extra work a discount needs to win

This is the figure nobody works out before agreeing. It only depends on two things: your margin and the size of the discount.

Your margin5% discount10% discount20% discount
20%+33% work+100% workNever breaks even
30%+20% work+50% work+200% work
40%+14% work+33% work+100% work
50%+11% work+25% work+67% work

Read the 20% margin row again. A 20% discount on a 20% margin means you are working for nothing, and anything beyond it means you are paying for the privilege of doing the job.

How this calculator works

Profit is what you charge minus what the job costs you. The discount comes straight off the profit, because your costs do not fall when your price does.

profit = price - cost profit after = (price - discount) - cost extra work needed = discount / (profit - discount)

The last line is the one that surprises people. If the discount is as large as your profit, the bottom of that fraction is zero and no amount of extra work ever covers it. The calculator says so plainly rather than printing an enormous number.

What to do instead of dropping the price

A client who asks for a discount is usually asking for something else: certainty, a smaller bill this month, or a reason to believe the price is fair. Each of those has a cheaper answer than money.

If you have already been discounting for years

Do not try to fix every client at once. Raise your rate with new clients first, where it costs you nothing, and let the discounted ones catch up at renewal. Work out what the discount has actually cost you over the last year before you decide how fast to move, because the number is usually the argument.

Next: check what you should be charging in the first place.

If the discount is only one part of the problem, the hourly rate calculator works out what you need to charge to cover your costs and pay yourself properly.

Open the rate calculator

FAQs

It depends entirely on your margin. On a 40% margin a 10% discount needs 33% more work to break even. On a 30% margin it needs 50% more. On a 20% margin it needs double. The discount comes out of your profit, not your price, which is why the answer is so much larger than 10%.

Everything you would not spend if the job did not happen: materials, subcontractors, travel, and your own time valued at what you would pay someone else to do it. Leave out rent and insurance, which you pay either way. Counting your own time as free is the most common way to make a bad discount look affordable.

Yes, when it buys something specific: a much larger order, a quiet month filled, payment up front, or a client you genuinely want as a reference. What rarely pays is a discount given to avoid an awkward conversation, because it wins the job at a price you will resent for as long as the work lasts.

Margin is profit as a share of the price you charge. Markup is profit as a share of what the job cost you. A job costing $1,300 sold at $2,000 carries a 35% margin and a 54% markup. This calculator works in margin, because a discount is taken off the price.

Do not defend the price, offer a choice. Show what the job looks like at a smaller scope for the budget they have, and leave the full version alongside it. The conversation moves from what it costs to what they get, and the client picks rather than negotiates.

Yes. It is completely free, with no signup. Your numbers stay in your browser unless you choose to email the result to yourself.

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